Research on the Farm: Sunflower Plant Population Trials Summarized (2021 – 2023)

Manitoba Crop Alliance’s Research on the Farm program looks at common agronomic, crop-specific concerns on field-scale, replicated trials in commercial fields. 2023 saw the sunflower plant population trials completed with 21 site-years of data.

The objective of this specific trial was to quantify the agronomic and economic impacts of various plant populations on both oilseed and confectionary sunflower production in Manitoba. Constant genetic improvements in sunflower hybrids raise the question of whether farmers can either increase or decrease their planting populations with improvements in quality and/or yield. Farmers took to the field to make that final decision.

Figure 1: MCA Research on the Farm Sunflower Plant Population Trial locations, 2021 – 2023.

Tone Ag Consulting performs MCA’s Research on the Farm trials in all 6 of our crop-types. In this specific trial type, they are helping the farmer with planting and harvest of the plots, plus taking some key information during the growing season. This includes soil sampling in the spring followed by growth stage notes and precipitation data during the season.

Table 1: Three-year summary of sunflower plant population trial for 21 site years. Six site-years contributed statistically significant yield differences which would provide profit for the farm, based only on seed prices.

When looking at this full data set, it doesn’t necessarily give a farmer the details they are looking for. At the end of the day, they want to know the ROI for each treatment, which includes spring seed costs and sunflower prices off the combine. Simply stated, if the “high” planting rate outyielded the “low” and “check” planting rates, it may have only been marginally, therefore the higher seed cost of planting at a high rate was likely not the economical choice.

Table 2: Three-year economic summary of sunflower plant population trial for 21 site years. Net profit per acre was calculated using estimated seed cost in spring 2023 and contract pricing in fall 2023.

Sunflower farmers tend to be aware of the best management practices for their farm, which is evident in Table 2, above. Planting populations are reasonably simple to set up on-farm and MCA recommends farmers make the effort to periodically do this same testing. 2022 and 2023 were dry years in areas of Manitoba, which may have skewed results, but it is important to continue to collect data in years of varying precipitation to determine planting rates that work better on your farm in all environments.